Field of the Invention
The present invention relates to an exhaust device that includes: a plurality of exhaust pipes for a multi-cylinder engine; and a collecting pipe connected to the downstream side portions of the exhaust pipes.
Description of Related Art
A multi-cylinder engine for a motorcycle has been known in which a plurality of exhaust pipes are collected and connected to a collecting pipe, and the collecting pipe is connected to a muffler, so that, after muffling of exhaust gas is performed by the muffler, the exhaust gas is discharged to the outside (for example, JP Laid-open Patent Publication No. H09-144535). In such an engine, the plurality of exhaust pipes and the collecting pipe are joined to each other by, for example, welding.
At a joining portion where the exhaust pipes each having a small diameter and the collecting pipe having a large diameter are joined to each other, a stepped portion is formed, whereby stress is likely to concentrate in the joining portion. In some cases, in order to avoid such concentration of the stress, a gusset is provided between the exhaust pipes and the collecting pipe so as to gradually vary the diameter of the exhaust pipes, whereby the stepped portion is less likely to be formed. However, in a structure in which such a gusset is provided, the number of components is increased and, further, welding process becomes complicated.